Electromagnetic control device



July 14, 1959 F. LEBER ELECTROMAGNETIC CONTROL DEVICE:

www m Filed Deo. 13, `1955 W s Y' l; il@

United States Patent O 2,895,089 ELECTROMAGNETIC CONTROL DEVICE Felix Leber, Koln-Riehl, Germany Application December 13, 1955, Serial No. 552,921 Claims priority, application Germany December 13, 1954 7 Claims. (Cl. 317-165) The present invention relates to a new and improved electro magnetic control device. More particularly, the present invention relates to a new `and improved control device including electromagnetic means for actuating an operating member. v

Electromagnetic operating members are used in connection with apparatus for various types of controls. For example, solenoids are used having a core member which is attracted into the solenoid proper or expelled therefrom when the solenoid is energized. The movement of the core member is used to operate any type of control member. For example, it can be used for operating electrical switches or mechanical valve arrangements.

When the electromagnetic member is energized, the core is attracted or repelled by the magnetic ilux established by the electromagnetic member or solenoid. However, when the electromagnetic member is deenergized some additional means are needed for returning the core member to its original undeflected position. That is, 'when the solenoid is deenergized the magnetic field established thereby breaks down and the core member is no longer attracted into Ithe solenoid. However, the break down of the magnetic ux has no effect upon the core member with respect to returning it to its position. It is accordingly conventional practice to use a coil spring member which normally urges the solenoid core member back into its undeected position. When the solenoid is energized, the magnetic iield established thereby must overcome the action of the coil spring in order to attract the core member into its deflected position.

Therefore, wi-th conventional electromagnetic control means the magnetic ilux established by the solenoid must move the core member and the control member to which it is connected against the action of the coil spring. It is therefore apparent that a large amount of the magnetic ux established by the solenoid is wasted in overcoming the action of the coil spring. It is clear that a quick acting electromagnetic contr-o1 member is advantageous. However, due to the time delay in the build up of the magnetic flux by the electromagnetic member, there is always some time 'lag betweenthe start of energization of the electromagnetic member and the movement of its core member into its deflected position. Therefore, it is highly desirable that the core member have a low inertia that is, only a small deflecting force should be required to start the core member moving from its initial position into its final deected position.

From the above it is clear that a high retaining spring force prevents the core member from moving quickly and prevents the electromagnetic control means including such a core member from being quick-acting. It would appear to be advantageous to have a spring member which has a very low restraining force while the core member is in its initial position and yet have a very large returning force to return the deflected core member back to its initial position.

If a coil spring is used, it is necessary to use a very long coil spring in order to provide the low initial restraining force. Also, the characteristics of a coil spring do not compare favorably to the characteristics of an electrically operated magnetic control member.

It is accordingly an object of the present invention to overcome the disadvantages of the above described conventional electromagnetic control devices.

A second object of the present invention is to provide a new and improved electromagnetic control device.

Still another object of the present invention is to provide a new and improved electromagnetic control member which is quick-acting and has substantially no time delay between its energization and its actuation.

A further object of Ithe present invention is to provide a new and improved electromagnetically controlled valve arrangement.

Yet a further object of the present invention is to provide a new and improved electromagnetic control device using leaf springs which are initially in an unstressed condition and which are stressed by the action of the actuating member of the electromagnetic means.

With the above objects in view, the present invention mainly consists of electromagnetic control apparatus including support means, an operating member movably mounted in the support means and movable between irst and second positions, electromagnetic means including an actuating member movable between energized and deenergized positions, the actuating member being adapted to move the operating member from its first to its second position when the electromagnetic means is energized to move the actuating member into its energized position, and at least one leaf spring normally urging the operating member and the actuating member into their first and unenergized positions respectively, the leaf spring being movable between unstressed and stressed conditions, whereby energization of the electromagnetic means moves lthe actuating member into its energized position and the operating member into its second position against the action of the leaf spring to place the leaf spring in its stressed condition.

In another embodiment the present invention includes an electromagnetic valve arrangement having a support member formed with at least an inlet passageway and an outlet passageway, a valve operating member movably mounted in one of lthe passageways and movable between a valve open position wherein the inlet and outlet passageways are in communication and a valve closed position wherein communication between the inlet and outlet passageways is blocked, at least one leaf spring movable between a stressed and an unstressed condition and connected to the valve operating member for urging the same into one of its positions when the leaf spring is in both its stressed and unstressed conditions, the urging being substantially stronger when the leaf spring is in its stressed condition than when in its unstressed condition, and electromagnetic actuating means movable between an energized and a deenergized position and connected to the valve operating member for moving the same, when energized, into the other of the positions against the action of the leaf spring and for simultaneously stressing the leaf spring whereby the leaf spring strongly urges the actuating means into is deenergized position and the valve operating member into the one position thereof only when the actuating means is in its energized position.

In another form of the present invention two leaf springs are used and are positioned with opposite curved portions thereof facing each other. In this position the two leaf springs provide very little restraining force in their unstressed condition but after Ithey are stressed by assenso the action of the actuating member of the electromagnetic means, they provide a very high restraining force.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a longitudinal cross sectional view of apparatus constructed in accordance with the present invention taken along the line I-I of Fig. 3 and showing the leaf springs thereof in unstressed condition;

Fig. 2 shows the apparatus of Fig. 'l with the leaf springs in stressed condition; and

' Fig. 3 is a sectional view taken along the line 111--111 of Fig. 1.

Referring to the drawings and particularly to Figs. l and 2, the electromagnetic control device incorporating the present invention is shown in connection with hydraulic valve arrangement mounted in the support means 1. A bushing 2 is iixedly mounted in the support means 1 and has a centrally located passageway 4 in which a valve operating member 3 is slidably mounted.

The valve operating member 3 has a reduced diameter in the central portion thereof and has wider diameter end pieces 5 and 6. Connected to the end piece 5 of the valve operating member 3 is a rod member 7 which passes through passageways in a first leaf spring and a second leaf spring 14 and terminates in a disc 18 mounted at the other side of the leaf spring 14. rfhe passageways in the leaf springs 14 and 1S are larger than the diameter of the rod member 7 as can clearly be seen in Fig. 3.

In the embodiment illustrated in Figs. 1 and 2 the leaf springs 14 and 15 are freely mounted on the upper surface 19 of the support means 1. Each of the springs 14 and 15 is arranged so that opposite curved portions thereof face each other and the only portions of the leaf springs which make contact with each other are the end portions thereof. It can be seen that the end portion 17 of the leaf spring 15 makes free contact with the end portion 16 of the leaf spring 14. That is, these end portions are not connected to each other in any way and the end portion 16 merely rests on end portion 17.

As can best be seen in Fig. 3, the lower leaf spring 15 is prevented from rotating about the rod 7 by means of pins 21 iixedly mounted in the upper surface 19 of the support means 1. It can be seen that the pins 21 are substantially adjacent the curved side portion of the spring 15. Similarly, the spring 14 is prevented from rotating by means of projections 23 mounted on the upper surface thereof. It can be seen that pins similar to the pins 21 can also be used for this purpose.

In Figs. l and 2 it can be seen that connected between the springs 14 and 15 and freely slidable on the rod 7 is a disc Ztl. Above the disc 1S mounted on the rod 7 is a rod 8 which has one of its ends threaded into a bushing 12 and which rod is locked in position by the lock nut 13. The other end of the bushing 12 is connected to a core member 9 of a solenoid 10 which is mounted in a housing 11. By the threaded rod 8 and the lock nut 13 it is possible to accurately position the valve control member 3 at either initial or the deflected position thereof.

The support means 1 is formed with an inlet passageway 25 which is adapted to be connected to a source of hydraulic fluid, for example. Also, a second passagewa namely an outlet passageway 24 is provided in the support means 1. it can be seen that the inner ends of the passageways 24 and 25 communicate vih annular depressions in the outer surface of the bushing 2 and with radially located, small diameter, passageways to the interior 4 of the bushing 2. In the position as shown in Fig. l, it is clear that any oil being supplied from the inlet passageway 25 is blocked from reaching the outlet passageway 24 by the end member 6 of the valve operating member 3. On the other hand, in the position shown in Fig. 2, it is clear that any oil supplied through the passageway 25 is free to iiow through the interior of the bushing 2 down to the passageway 24. The outlet passageway 24 is adapted to be connected to a hydraulically operated piston, for example.

In operation, the apparatus shown in Fig, l is in the initial or deenergized position. The leaf springs 14 and 15 are in their unstressed condition and it can be seen that the end portions 17 of the leaf spring 15 is out of contact with the support means 1. Accordingly, the leaf springs 14 and 15 provide very little restraining force with respect to the actuating member or core 9 of the solenoid 111 and the intermediate rod connections 8 and 12. It is apparent that the springs 14 and 15 may have their curvature so arranged that the only restraining force provided, in their unstressed condition, is just sufficient to support the weight of the core member 9 and the intermediate rods S and 12. ln the event that the apparatus of Fig. l is mounted in a horizontal plane the leaf springs 14 and 1S do not even have to support the weight of the members.

In Fig. 1 it can be seen that the core 9 of the solenoid 1t) is in its ejected position where a substantial portion thereof is outside of the winding of the solenoid 10. When the solenoid 1t) is energized, the current owing through the winding thereof will establish a magnetic flux therein and attract the core member 9 into the solenoid 111. This moves the intermediate rod members 8 and 12 and actuates the valve control member 3 by means of the rod 7. The control member 3 is moved from inoperative position of Fig. l into the operative position of Fig. 2. At the same time the actuating member composed of core 9 and rod 8 moves the leaf springs 14 and 15 from unstressed into stressed condition. Therefore, after the current flowing through the solenoid 11B has reached its maximum amount and the core 9 of the solenoid has been attracted into the solenoid, the leaf springs 14 and 15 being in stressed condition, provide a very strong returning force. However, this force is easily overcome by the magnetic flux established in thc solenoid due to the maximum amount of current lowing therein.

Accordingly, when the solenoid is deenergized and the magnetic field set up by the solenoid breaks down, the strong restoring force of the stressed springs 14 and 15 immediately acts to return all of the actuating and operating members back to the original positions shown in Fig. 1.

Therefore, by means of the present invention instant operation of the hydraulic valve illustrated is possible. As soon as the solenoid is energized the valve operating member 3 is moved from inoperative or blocking position into operative or transmitting position to prevent oil flowing from the passageway 2S to iiow freely to the passageway 24.

The characteristics of the electromagnetic control member such as the solenoid 10 are such that the initial magnetic flux established thereby is relatively low while the final magnetic flux established is relatively high. Therefore, it is desirable to have a spring member which has a similar characteristic. It can be seen that by the arrangement of the leaf springs 14 and 15, the initial urging force of the leaf springs is relatively low but this urging force becomes stronger and stronger as the springs are moved into stressed condition. Finally, when the magnetic flux is at its maximum, the restoring force of the springs is also at a maximum. It is therefore seen that the springs provided by the present invention have a restoring force or returning force characteristic which is precisely the equivalent of the characteristic of the solenoid 10. This advantageous characteristic of the leaf assaoss springs is due to the increasing resistance offered by the springs 14 and 15 as they are placed in stressed condition. This increased resistance is due to the fact that the contact line between the two springs moves closer and closer together as the springs are placed in stressed condition so that the free spring portion of the leaf springs 14 and 15 become smaller. In this manner the spring constant of the two leaf springs is increased. That is, it can be seen that the distance between the contacting end portions of the leaf springs 14 and 15 in Fig. 1 is longer than the distance between the contacting end portions of the stressed leaf springs in Fig. 2. Because the spring portion is shorter in Fig. 2 it has an increased restoring force available.

It will be understood that each of the elements described above, or two or more together, may also nd a useful application in other types of electromagnetically controlled devices ditfering from the types described above.

. While the invention has been illustrated and described as embodied in electromagnetically operated valve arrangements, it is not intended to be limited to the details shown, since various modications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current Iknowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended lwithin the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A spring assembly, comprising, in combination, a support means; an operating stern member movable relative to said support means in longitudinal direction thereof, said stem member having one end thereof located in the region of said support means and being connected at the other end thereof to the core of an electromagnetic means so as to be moved toward said support means from a iirst position to a second position when the electromagnetic means is energized; a rst leaf spring extending transverse to said stem member and having a center portion concave toward said support means and a pair of end portions convex to said support means, said center portion having an opening through which said stem member passes; means securing said stem member to said center portion of said first leaf spring; and a second leaf spring extending transverse to said stem member and having a center portion convex toward said support means and a pair of end portions concave to said support means, said center portion being supported on said support means and having an opening through which said stem member freely passes, said end portions of said leaf springs abutting each other in said rst position of said stern member whereby during movement of said stem member from said first position to said second position said center portions of said leaf springs are attened so that the points of engagement between said leaf springs travel inwardly -whereby said center portions are shortened and said end portions are lengthened and the associated ends of said tirst and second leaf springs move away from each other so that the resilient resistance of said leaf springs increases at a low initial rate and then increases at a substantially higher rate corresponding to the electromagnetic force acting on the core.

2. A spring assembly, comprising, in combination, a support means; an operating stem member movable relative to said support means in longitudinal direction thereof, said stem member having one end thereof located in the region of said support means and being adapted to be moved toward said support means from a iirst position to a second position; a first leaf spring extending transverse to said stem member and having a center portion concave toward said support means and a pair of end portions convex to said support means, said center portion having an opening through which said stem member passes; means securing said stem member to said center portion of said iirst leaf spring; and a second leaf spring extending transverse to said stem member and having a center portion convex toward said support means and a pair of end portions concave to said support means, said center portion being supported on said support means and having an opening through which said stem member freely passes, said end portions of said leaf springs abutting each other in said lirst position of said stem member whereby during movement of said stem member from said first position to said second position said center portions of said leaf springs are attened so that the points of engagement between said leaf springs travel inwardly whereby said center portions are shortened and said end portions are lengthened and the associated ends of said rst and second leaf springs move away from each other so that the resilient resistance of said leaf springs increases at a low initial rate and then increases at a substantially higher rate.

3. A spring assembly, comprising, in combination, a support means having a bore; an operating stem member movable relative to said support means in longitudinal direction thereof, said stem member having one end thereof located in said bore of said support means and being connected at the other end thereof to the core of an electromagnetic means so as to be moved toward said support means from a first position to a second position when the electromagnetic means is energized; a first leaf spring extending transverse to said stem member and having a center portion concave toward said support means and a pair of end portions convex to said support means, said center portion having an opening through which said stem member passes; means securing said stem member to said center portion of said first leaf spring; a second leaf spring extending transverse to said stem member and having a center portion convex toward said support means and a pair of end portions concave to said support means, said center portion being supported on said support means and having an opening through which said stem member freely passes, said openings in said leaf springs and said bore being aligned, said end portions of said leaf springs abutting each other in said first position of said stem member whereby during movement of said stem member from said first position to said second position said center portions of said leaf springs are attened so that the points of engagement between said leaf springs travel inwardly whereby said center portions are shortened and said end portions are lengthened and the associated ends of said first and second leaf springs move away from each other so that the resilient resistance of said leaf springs increases at a low initial rate and then increases at a substantially higher rate corresponding to the electromagnetic force acting on the core; and means on said support means engaging said second leaf spring laterally to prevent turning of said second leaf spring about said stem member.

4. A spring assembly, comprising, in combination, a support means having a bore; an operating stem member movable relative to said support means in longitudinal direction thereof, said stem members having one end thereof located in said bore of said support means and being connected at the other end thereof to the core of an electromagnetic means so as to be moved toward said support means from a rst position to a second position when the electromagnetic means is energized; a first leaf spring extending transverse to said stem member and having a center portion concave toward said support means and a pair of end portions convex to said support means, said gaseoso center portion having an opening through which said stem `member passes; means securing said stern member to said center portion of said rst leaf spring; a second leaf spring extending transverse to said stern member and having a center portion convex toward said support means and a pair lof end portions concave to said support means, said center portion being supported on said support means and having an opening through which said stem member freely passes, said openings in said leaf springs and said bore being aligned, said end portions of said leaf springs abutting each other in said rst position of said stem member whereby during movement of said stem member from said rst position to said second position said center portions of said leaf springs are flattened so that the points of engagement between said leaf springs ltravel inwardly whereby said center portions are shortened and said end portions lare lengthened and the associated ends of said 'lirst and second leaf springs move away from each other so that the resilient resistance of said leaf springs increases at a low initial rate and then increases at a substantially higher rate corresponding to the electromagnetic force acting on the core; and a pair of pins extending in direction of said stern member spaced from the same and being secured to said support means, said pins laterally engaging in said first position of said stem member said second leaf spring to prevent turning of the same about said stem member, and laterally engaging both said `leaf springs in said second position of said stem member.

5. A spring assembly, comprising, in combination, a support means having a bore; an operating stem member movable relative to said support means in longitudinal direction thereof, said stem member having one end thereof located in said bore of said support means and being connected at the other end thereof to the core of an electromagnetic means so as to be moved toward said support means from a first position to a second position when the electromagnetic means is energized; a first leaf spring extending transverse to said stem member and having a center portion concave toward said support means and a pair of end portions convex to said support means, said center portion having an opening through which said stem member passes; means securing said stem member to said center portion of said first leaf spring; a second leaf spring extending transverse to said stem member and having a center portion convex toward said support means and a pair of end portions concave to said support means, said center portion being supported on said support means and having an opening through which said stem member freely passes, said openings in said leaf springs and said bore being aligned, said end portions of said leaf springs abutting each other in said first position of said stem member whereby during movement of said stem member from said iirst position to said second position said center portions of said leaf springs are flattened so that the points of engagement between said leaf springs travel inwardly whereby said center portions are shortened and said end portions are lengthened and the associated ends of said first and second leaf springs move away from each other so that the resilient resistance of said leaf springs increases at a low initial rate and then increases at a substantially higher rate corresponding to the electromagnetic force acting on the core; and a block located between said center portions of said leaf springs and having a bore through which said stem member passes, said block engaging both said center portions in said second position of said stem member to space said center portions from each other.

'6. A spring assembly, comprising, in combination, a support means having a bore; an operating stem member movable relative to said support means in longitudinal direction thereof, said stem member having one end there of located in said bore of said support means and being connected at the other end thereof to the core of an electromagnetic means so as to moved toward said support means from a rst position to a second position when the electromagnetic means is energized; a first leaf spring extending transverse to said stem member and having a center portion concave toward said support means and a pair of end portions convex to said support means, said center portion having an opening through which said stem member passes; means securing said stem member to said center portion of said rst leaf spring; a second leaf spring extending transverse to said stern member and having a center portion convex toward said support means and a pair of end portions concave to said support means, said center portion being supported on said support means and having an opening through which said stem member freely passes, said openings in said leaf springs and said bore being aligned, said end portions of said leaf springs abutting each other in said rst position of said stem member whereby during movement of said stem member from said rst position to said second position said center portions of said leaf springs are attened so that the points of engagement between said leaf springs travel inwardly whereby said center portions are shortened and said end portions are lengthened and the associated ends of said iirst and second leaf springs move away from each other so that the resilient resistance of said leaf springs increases at a low initial rate and then increases at a substantially higher rate corresponding to the electromagnetic force acting on the core; means on said support means engaging said second leaf spring laterally to prevent turning of said second leaf spring about said stern member; and a block located between said center portions of said leaf springs and having a bore through which said stem member passes, said block engaging both said center portions in said second position of said stern member to space said center portions from each other.

7. A spring assembly, comprising, in combination, a support means; an operating stem member movable relative to said support means in longitudinal direction thereof, said stem member having one end thereof located in said bore of said support means and being adapted to be moved toward said support means from a rst position to a second position; a first leaf spring extending transverse to said stem member and having a center portion concave toward said support means and a pair of end portions convex to said support means, said center portion having an opening through which said stem member passes; means securing said stem member to said center portion of said rst leaf spring; a second leaf spring extending transverse to said stem member and having a center portion convex toward said support means and a pair of end portions concave to said support means, said center portion being supported on said support means and having an opening through which said stem member freely passes, said end portions of said leaf springs abutting each other in said rst position of said stem member whereby during movement of said stern member from said first position to said second position said center portions of said leaf springs are flattened so that the points of engagement between said leaf springs travel inwardly whereby said center portions are shortened and said end portions are lengthened and the associated ends of said rst and second leaf springs move away from each other so that the resilient resistance of said leaf springs increases at a low initial rate and then increases at a substantially higher rate; means on said support means engaging said second leaf spring laterally to prevent turning of said second leaf spring about said stem member; and a block located between said center portions of said leaf springs and having a bore through which said stem member passes, said block engaging both said center portions in said second position of said stem member to space said center portions from each other.

(References on following page) References Cited in the le of this patent UNITED STATES PATENTS Cole July 16, 1889 Holdsworth Nov. 22, 1927 5 Harrall June 9, 1936 Paget Sept. 3, 1940 Osgood July 18, 1944 

